DALLAS (SMU) – New research from SMU’s Geothermal Laboratory, funded by a
grant from Google.org, documents significant geothermal resources
across the United States capable of producing more than three million
megawatts of green power – 10 times the installed capacity of coal power
plants today.

Sophisticated mapping produced from the research, viewable via Google Earth at www.google.org/egs, demonstrates
that vast reserves of this green, renewable source of power generated
from the Earth’s heat are realistically accessible using current
technology.

The results of the new research, from SMU Hamilton Professor of
Geophysics David Blackwell and Geothermal Lab Coordinator Maria
Richards, confirm and refine locations for resources capable of
supporting large-scale commercial geothermal energy production under a
wide range of geologic conditions, including significant areas in the
eastern two-thirds of the United States. The estimated amounts and
locations of heat stored in the Earth’s crust included in this study are
based on nearly 35,000 data sites – approximately twice the number used
for Blackwell and Richards’ 2004 Geothermal Map of North America, leading to improved detail and contouring at a regional level.

Based on the additional data, primarily drawn from oil and gas
drilling, larger local variations can be seen in temperatures at depth,
highlighting more detail for potential power sites than was previously
evident in the eastern portion of the U.S. For example, eastern West
Virginia has been identified as part of a larger Appalachian trend of
higher heat flow and temperature.

Conventional U.S. geothermal production has been restricted largely
to the western third of the country in geographically unique and
tectonically active locations. For instance, The Geysers Field north of
San Francisco is home to more than a dozen large power plants that have
been tapping naturally occurring steam reservoirs to produce
electricity for more than 40 years.

However, newer technologies and drilling methods can now be used to
develop resources in a wider range of geologic conditions, allowing
reliable production of clean energy at temperatures as low as 100˚C
(212˚F) – and in regions not previously considered suitable for
geothermal energy production. Preliminary data released from the SMU
study in October 2010 revealed the existence of a geothermal resource
under the state of West Virginia equivalent to the state’s existing
(primarily coal-based) power supply.

"Once again, SMU continues its pioneering work in demonstrating the
tremendous potential of geothermal resources,” said Karl Gawell,
executive director of the Geothermal Energy Association. “Both Google
and the SMU researchers are fundamentally changing the way we look at
how we can use the heat of the Earth to meet our energy needs, and by
doing so are making significant contributions to enhancing our national
security and environmental quality."

"This assessment of geothermal potential will only improve with
time," said Blackwell. “Our study assumes that we tap only a small
fraction of the available stored heat in the Earth’s crust, and our
capabilities to capture that heat are expected to grow substantially as
we improve upon the energy conversion and exploitation factors through
technological advances and improved techniques."

Blackwell is releasing a paper with details of the results of the
research to the Geothermal Resources Council on October 25, 2011.

Blackwell and Richards first produced the 2004 Geothermal Map of North America
using oil and gas industry data from the central U.S. Blackwell and
the 2004 map played a significant role in a 2006 Future of Geothermal
Energy study sponsored by the U.S. Department of Energy that concluded
geothermal energy had the potential to supply a substantial portion of
the future U.S. electricity needs, likely at competitive prices and with
minimal environmental impact. SMU’s 2004 map has been the national
standard for evaluating heat flow, temperature and thermal conductivity
for potential geothermal energy projects.

In this newest SMU estimate of resource potential, researchers used
additional temperature data and in-depth geological analysis for the
resulting heat flow maps to create the updated temperature-at-depth maps
from 3.5 kilometers to 9.5 kilometers (11,500 to 31,000 feet). This
update revealed that some conditions in the eastern two-thirds of the
U.S. are actually hotter than some areas in the western portion of the
country, an area long-recognized for heat-producing tectonic activity.
In determining the potential for geothermal production, the new SMU
study considers the practical considerations of drilling, and limits the
analysis to the heat available in the top 6.5 km (21,500 ft.) of crust
for predicting megawatts of available power. This approach incorporates a
newly proposed international standard for estimating geothermal
resource potential that considers added practical limitations of
development, such as the inaccessibility of large urban areas and
national parks. Known as the ‘technical potential’ value, it assumes
producers tap only 14 percent of the ‘theoretical potential’ of stored
geothermal heat in the U.S., using currently available technology.

Three recent technological developments already have sparked
geothermal development in areas with little or no tectonic activity or
volcanism:

Low Temperature Hydrothermal – Energy is produced from areas with naturally
occurring high fluid volumes at temperatures ranging from less than boiling to
150°C (300°F). This application is currently producing energy in Alaska, Oregon,
Idaho and Utah.

Geopressure and Coproduced Fluids Geothermal – Oil and/or natural gas are
produced together with electricity generated from hot geothermal fluids drawn
from the same well. Systems are installed or being installed in Wyoming, North
Dakota, Utah, Louisiana, Mississippi and Texas.

Enhanced Geothermal Systems (EGS) – Areas with low fluid content, but high
temperatures of more than 150°C (300°F), are “enhanced” with injection of fluid
and other reservoir engineering techniques. EGS resources are typically deeper
than hydrothermal and represent the largest share of total geothermal resources
capable of supporting larger capacity power plants.

A key goal in the SMU resource assessment was to aid in evaluating these
nonconventional geothermal resources on a regional to sub-regional basis.

Areas of particular geothermal interest include the Appalachian trend
(Western Pennsylvania, West Virginia, to northern Louisiana), the aquifer heated
area of South Dakota, and the areas of radioactive basement granites beneath
sediments such as those found in northern Illinois and northern Louisiana. The
Gulf Coast continues to be outlined as a huge resource area and a promising
sedimentary basin for development. The Raton Basin in southeastern Colorado
possesses extremely high temperatures and is being evaluated by the State of
Colorado along with an area energy company.

SMU’s Geothermal Laboratory in Dedman College of Humanities and Sciences
conducted this research through funding provided by Google.org, which is
dedicated to using the power of information and innovation to advance
breakthrough technologies in clean energy.

###_____________________________________________________________________________________________Editor's Note: To explore the new Enhanced Geothermal
Systems maps built on SMU's research via Google Earth, you will need to download
the latest version of Google Earth here and then download and open the file at http://www.google.org/egs/downloads/EGSPotential.kmz.

###

This story was originally published on the SMU (Southern Methodist University) website and was republished with permission.